Flutter:组合ScrollView和PageView小部件

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        body: NestedScrollView(
          headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) {
            return <Widget>[
              SliverAppBar(
                title: Text('Flutter Demo'),
                floating: true,
                pinned: true,
                snap: true,
                expandedHeight: 200,
                flexibleSpace: FlexibleSpaceBar(
                  background: Image.network(
                    'https://example.com/image.jpg',
                    fit: BoxFit.cover,
                  ),
                ),
              ),
            ];
          },
          body: PageView(
            children: <Widget>[
              Container(
                color: Colors.red,
                child: Center(
                  child: Text('Page 1'),
                ),
              ),
              Container(
                color: Colors.blue,
                child: Center(
                  child: Text('Page 2'),
                ),
              ),
              Container(
                color: Colors.green,
                child: Center(
                  child: Text('Page 3'),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}